E-M1 long exposure noise issue: Buy a different backup-body or change pp-software?

The E-M1's noise issue when exposing for a minute or so and longer is well established. I know it has been improved with the firmware-updates, but it is still there.

I use mainly Aperture, and the files hardly take any beating before serious chroma-noise appears. I do not mind luminance noise too much, but the ugly green and yellow blotches that appear when lifting the shadows ever so slightly or even when raising the blacklevel is too much to bear.

I remember back in '04 when I was shooting nightime landscapes with my D70, there was much cleaner shadows than this.

So, my question is this: Have anyone here found a good way to get clean, crisp files with the E-M1 at base iso with long exposures?

Or should I just buy a body for this single purpose, a cheap DSLR with good sensor like the D5200?

Much as I hate to say this as a long time Aperture user (from v1.0) but download the trial version of Lightroom and see how well it's noise reduction features work compared to Aperture. It has separate controls for Luma and Chroma noise (I usually add some chroma noise reduction, sometimes without luma) as well as detail controls etc.

Unfortunately NR in Lightroom is way ahead of Aperture.

I just went through the process of moving an 82,000 image library from Aperture to Lightroom 5

I found doing dark frame subtraction works reasonably well (take 20-30 shots of the same duration as the original, average them and subtract from the real exposure) however it doesn't work very well if you're planning on pushing and pulling large areas in RAW (As changing settings on one is different to the other with the same changes, different parts are highlights/shadows etc). The noise appears to be static and is near identical from one exposure to the next...

The best solution I had was using a different body, I believe the E-M5 is meant to be one of the better bodies for longer exposures as it uses the sony sensor.